Flat needlefish

The flat needlefish (Ablennes hians), or barred longtom,^[3] the only known member of the genus Ablennes, is a marine fish of the family Belonidae. Flat needlefish are considered gamefish, frequently caught with the help of artificial lights,^[4] but are not often eaten because of their green-colored flesh.^[5]

Flat needlefish
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Beloniformes
Family:	Belonidae
Genus:	Ablennes D. S. Jordan & Fordice, 1887[2]
Species:	A. hians
Binomial name
Ablennes hians Valenciennes, 1846
Synonyms
Ablennes pacificus Walford, 1936 Belone hians Valenciennes, 1846 Belone maculata Poey, 1860 Belone melanostigma Valenciennes, 1846 Belone schismatorhynchus Bleeker, 1850 Mastaccembelus melanostigma Valenciennes, 1846 Mastacembelus fasciatus Bleeker, 1873 Tylosurus caeruleofasciatus Stead, 1908 Tylosurus hians Valenciennes, 1846

The generic name Ablennes – formerly misspelled Athlennes – means ‘without mucosity’,^[6] from the ancient Greek privative a- prefix and blennos (‘mucus’). Its specific name hians is Latin for "gaping".

Description

Although they have no spines, they do have several soft rays. About 23-26 rays are on the dorsal fin and 24-28 are on the anal fin.^[7] They have 86-93 vertebrae.^[7] Dorsally, flat needlefish are blueish, white ventrally, with dark blotches and 12-14 vertical bars in the middle of their bodies.^[8] Flat needlefish have elongated bodies, with scythe-shaped pectoral and anal fins.^[7] They also have a dark lobe on the posterior part of their dorsal fins.^[7]

The longest recorded flat needlefish measured 140 cm.^[9] Measurements for flat needlefish body length do not include their caudal fins and heads because the fish's long jaws are often broken off.^[7] The largest recorded weight for a flat needlefish was 4.8 kg.^[9]

Distribution and habitat

Flat needlefish are found worldwide in tropical and temperate seas.^[7] In the Eastern Atlantic, they are known from Cape Verde and Dakar to Moçamedes in Angola.^[10] In the western Atlantic, they are known from the Chesapeake Bay south to Brazil.^[11] They are found throughout the Indian Ocean,^[7] and in the western Pacific from the southern islands of Japan to Australia^[12] and Tuvalu.^[13] A few specimens have been collected from Syria to Israel in the Mediterranean Sea,^[14] likely migrants from the Red Sea.

Flat needlefish usually live in neritic ocean waters near islands,^[15] estuaries,^[16] and near coastal rivers,^[17] where they feed on smaller fish^[4] and occasionally gather in large schools.^[5]

Reproduction

Flat needlefish lay eggs, which attach themselves to floating debris by filaments on the surface of each egg.^[18] Only the left gonad in both sexes is developed, and in males, the right gonad is sometimes wholly absent.^[19]